The present invention relates to a driving apparatus for lifting up and/or down a moving cage of an elevator.
Referring to FIG. 4, a conventional driving apparatus for use in an elevator will be described which is disclosed in JP-B-63-3823. This driving apparatus 1 has a speed reducer 2, an electric motor device 3 for rotationally driving an input shaft 2b of the speed reducer 2, a sheave 4 adapted to be rotationally driven by an output shaft 2d of the speed reducer 2, an ordinary electromagnetic brake device 8 mounted on the electric motor device 3 for braking the input shaft 2b, and an emergency electromagnetic brake device 9 mounted on the output shaft 2d for braking the output shaft 2d. When the input shaft 2b of the speed reducer 2 is rotationally driven by the electric motor device 3, the output shaft 2d rotates via a supporting shaft f and a supporting plate 2e at a slower speed resulting when the rotation of the input shaft is frictionally transmitted via a roller 2c, a roller 2g and a friction element 2h, and then the sheave 4 is rotationally driven. When the transmission of the power of the input shaft becomes impossible due to the friction generated by the roller 2c and the like, upon detection of this abnormal state, the emergency electromagnetic brake device 9 is activated and the brakes are applied to the output shaft 2d, whereby the sheave 4 is brought to a halt.
According to the driving apparatus for an elevator as described above, however, the emergency electromagnetic brake device 9 is secured to the output shaft 2d and is provided so as to extend in the direction of the input shaft, this making the brake device larger. In addition, the ordinary electromagnetic brake device 8 is also provided so as to extend in the input shaft direction. Thus, the entirety of the driving apparatus had to be made thicker with respect to the axial direction of the input shaft. This in turn serves to make larger an elevator room in a building where the driving apparatus and the like are placed. Additionally, the supporting shaft 2f which is coupled to the output shaft 2d is of a cantilever type in which the output shaft is supported on the supporting plate 2e, and this facilitates the deformation through deflection, which is not good in terms of the rotation transmission capability.
An object of the invention is to provide a driving apparatus for an elevator in which not only can a brake device be miniaturized but also the entirety of the driving apparatus itself can be made thinner in a direction of an input shaft.
With a view to attaining the above object, there is provided a driving apparatus for an elevator comprising an electric motor device, an input shaft adapted to be rotationally driven by the electric motor device, rotary elements disposed in such a manner as to be in contact with a circumferential surface of the input shaft so as to rotate as the input shaft rotates, supporting members fixed in such a manner as to rotatably support the rotary elements, a cylindrical element disposed in such a manner as to be in contact with the rotary elements on an inner circumferential surface thereof so as to rotate as the rotary elements rotate, a sheave provided on an outer circumferential side of the cylindrical element, adapted to rotate together with the cylindrical element and configured so as to be wound therearound with ropes for lifting up and/or down a moving cage of the elevator, and a brake device disposed in a radial direction of the sheave for braking a brake disc constructed so as to extend in the radial direction and secured to the sheave.
According to the invention, the rotation of the input shaft is transferred through frictional transmission to the cylindrical element and the sheave via the rotary elements to thereby rotate the cylindrical element and the sheave, but the rotary elements, cylindrical element and sheave are provided in diametrical directions of the input shaft and the brake device including the brake disc is provided in radial directions of the sheave, whereby the entirety of the brake apparatus can be made thinner in the direction of the input shaft. In addition, the brake disc is located radially outwardly of the sheave and this increases the radius thereof, whereby with the brake disc so constructed, in order to obtain a certain magnitude of braking force there is needed only a smaller magnitude of braking force than one needed with a brake disc other than the brake disc according to the invention. This helps miniaturize the brake apparatus. Note that in a case where there are provided a plurality of rotary elements, the plurality of rotary elements are disposed in such a manner as to be in internal contact with the inner circumferential surface of the cylindrical element. In addition, the brake device can be installed such that it extends from the supporting member of the driving apparatus.
In addition, there is provided a driving apparatus for an elevator, wherein the rotary elements are provided in such a manner as to rotate about intermediate shafts, and wherein the intermediate shafts are rotatably supported by the supporting members at ends thereof. According to this construction, the rotary elements are supported in a stable fashion and they can rotate in a smooth fashion, whereby rotations from the electric motor device are transferred as far as the sheave in a smooth fashion, thereby making it possible to improve the rotational transfer capability.
Furthermore, there is provided a driving apparatus for an elevator, wherein there are provided a plurality of the brake devices. Since the brake device is disposed in the radial direction of the sheave, it is possible to set a plurality of, for instance, two brake devices, whereby if the same magnitude of brake torque as that which would be obtained with a single brake device is tried to be obtained with the entirety of the brake disc, the respective brake devices can further be miniaturized. In addition, one of the two brake devices may be adapted to be activated for operation at normal times and the other to be activated for operation for emergency.
The present disclosure relates to the subject matter contained in Japanese patent application No. Hei. 11-154508 (filed on Jun. 2, 1999), which is expressly incorporated herein by reference in its entirety.